At the present time, while solving various problems on electronic computers, it is required in increasing frequency to accomplish the flexible input of problem-related data from one operator's position, for example, in cases when the computer system is used on flying vehicles, in the operation of microcalculators and the like. In such cases the data input keyboard should enable the input of a few different alphabets or sets of characters and formatized instructions individually required by each of the users solving problems of a different nature. If, however, the characters required by different users for the solution of their specific problems do not coincide partially or completely, then the number of these characters tends to increase and, accordingly, so does the number of the keys in the keyboard. The present invention is directed at the provision of a universal keyboard for the input of data into a computer system, allowing the input of characters of a few alphabets and a simple change of the alphabets with a minimum number of keys in the keyboard.